1. Field of the Invention
The present invention relates to a packaging box and a sheet for the packaging box to be used for packing a wire for welding and other and, more particularly, to a packaging box and a sheet for the packaging box that have been improved in portability.
2. Description of the Prior Art
The wire for welding is usually wound into a form of a cylinder around a coil core. During a period of storage in a warehouse for products after delivery from a manufacturing factory, shipping, transport, and delivery to an end user, the welding wire is packaged in a rectangular parallelepiped corrugated fiberboard box. That is to say, the wire for welding thus coiled on the core is carried in the rectangular parallelepiped corrugated fiberboard box.
This wire for welding, however, is very heavy, weighing for example 20 kg a roll. This heavy material is packaged in for example a 280 mm wide and 110 mm high corrugated fiberboard box.
A worker, when carrying a welding wire, first tilts a corrugated fiberboard box containing the welding wire, inserts one hand between the bottom of one edge of the box and the floor and then the other hand between the bottom of the other edge of the box and the floor. After the insertion of the hands, the worker lifts and carries the box to a specific position. However, it is not easy to lift such a heavy object with the hands and feet set in unstable and uncomfortable positions, and the transportation of the object is hard work. It is possible that there occurs a lifting-associated injury such as a pain in the back, or a transport-associated accident such as the drop of the object off the hands onto his foot. Particularly since the worker usually wears gloves, the corrugated fiberboard box is likely to slip off the hands if handled carelessly, giving an injury to his foot.
There has been proposed in Japanese Unexamined Patent Publication No. Hei 3-14449 a packaging box having concaved sections provided each in the central part of a ridgeline by providing a pair of folding lines in parallel with one ridgeline at the central part of this ridgeline and also providing a cutting line connecting the ends of each folding line to each other. The worker can carry the box with the hands reaching and gripping the box at these concaved sections. This type of box, however, has such a disadvantage as low strength because these concaved sections are formed by cutting part of the box. Furthermore the box with these concaved sections has holes thereat, resulting in defective packaging.